1. Field of the Invention
The present invention relates to an electrical connector, and more particularly to a high speed Serial Attached SCSI (Small Computer System Interface) (SAS) connector mounted on a printed circuit board (PCB).
2. Description of the Related Art
Parallel ATA (Advanced Technology Attachment) and parallel SCSI are two dominant disk interfaces technologies today. The parallel ATA disks are widely used in desktop PCs and mobile PCs, and the parallel SCSI disks are mainly used in high-volume servers and subsystems. As disk interconnect speeds continue to rise, existing parallel ATA and parallel SCSI buses are reaching their performance limits because that parallel transmissions are susceptible to crosstalk across multiple streams of wide ribbon cable that adds line noise and can cause signal errors—a pitfall that has been remedied by slowing the signal, limiting cable length or both. Therefore, new interconnect technologies are needed to meet performance requirements going forward. The serial technology is emerging as a solution to the problem. The main advantage of serial technology is that while it does move data in a single point-to-point stream, it does so much faster than parallel technology because it is not tired to a particular clock speed.
Serial ATA (SATA) is a serial version of ATA, which is expected to be a replacement for parallel ATA. U.S. Pat. No. 6,331,122 discloses a type of SATA receptacle connector for being mounted on a Printed Circuit Board. The receptacle connector has two receiving cavities defined in an insulative housing thereof and two sets of conductive contacts respectively used for power and signal transmission installed in the insulative housing. U.S. Pat. No. D469,407 discloses an electrical connector assembly with a SATA plug connector as a part thereof. The plug connector has two generally L-shaped tongue plates receiving two sets of terminals for electrically connecting the conductive contacts as the tongue plates are inserted into the respective receiving cavities of the receptacle connector.
Serial Attached SCSI (SAS) is a successor to the parallel SCSI and is also based on serial technology. Besides the advantage of higher speed signal transmission, another most significant advantage is the SAS interface will also be compatible with SATA drives. In other words, the SATA plug connector can plug directly into an SAS receptacle connector if supported in the system. By this way, the system builders are flexible to integrate either SAS or SATA devices and slash the costs associated with supporting two separate interfaces.
The SAS receptacle connector has generally the same configuration as the SATA receptacle connector except that the two cavities of the SATA receptacle connector are merged in a large one of the SAS receptacle connector, and a third sets of signal contacts are assembled to a second side wall opposing a first side wall where two sets of contacts have already being assembled. However, the second side wall is much thinner in a lateral direction of the connector than the first side wall. Thus, it is difficult to provide passageways in such second side wall like in the first side wall for receiving contacts and allowing the contact portion of each to be moveable therein. If the third sets of contacts are directly adhered on an inner face of the second side wall with each contact portion curved away from the inner face, when an SAS plug connector mates with the SAS receptacle connector, terminals of the SAS plug connector tightly abut against the corresponding contacts of the SAS receptacle connector to establish an electrical connection therebetween. However, the contact portion of each contact is inevitably deformed toward the inner face after a long term pressure of the terminal, which will reduce the normal contacting force between the contact and the terminal, thereby causing the electrical connection therebetween unreliable or even break.
Hence, an improved electrical connector is required to overcome the disadvantages of the prior art.